Lucene is a highly reliable and very widely deployed search engine, first established in 1999. Lucene has been an Apache open source project since 2001

Elasticsearch is a comparatively recent development which was first launched 2010. Unlike Lucene and Solr, ElasticSearch is not a project of the Apache Software Foundation, but is based at Github, a commercial software hosting service. Elasticsearch is however licensed for use under the same Apache 2.0 License as Solr

Solr is an enterprise search platform based on Lucene, and has been in open source since 2006. Solr is very widely used, and is supported by an Apache community of more than 100 developers and code committers

Newer, but already very widely used, Elasticsearch is being developed with more focus than Solr, and that focus is on extracting value from data generally, and not just on search. In other words, as well as being a highly capable search platform, Elasticsearch is also part of the "ELK stack" - Elasticsearch, Logstash, Kibana, as a big data analysis solution

Elasticsearch makes it easier to create and implement large search systems

It is schema-free and document-oriented, and for many projects, these are important technical innovations

ElasticSearch has been designed with the cloud era in mind

Elasticsearch claims that more than a million downloads per month are being made as of June 2014

SOLR

Simply through its maturity, wide deployment, and active developer community, Solr tends to be favored by experienced technical staff

Solr provides a highly detailed functional environment, a wide range of plug-ins are available, and has a large, diverse developer community

COMMERCIAL MODELS

Some of the originators of Solr subsequently formed a commercial company Lucidworks (publicly launched 2009 as Lucid Imagination) which provides a licensable enterprise search system built on Solr. Lucidworks was launched at a time when a substantial development community for Solr had already been established

A company was launched in 2014 parallel around Elasticsearch (which is now known as Elastic), and as of June 2014, Elasticsearch has raised more than $100million in venture capital. The commercial company offers a range of reasonably-priced support packages both for development and production environments (Search Technologies is an authorized reseller of these services)

DEPLOYING ELASTICSEARCH AND SOLR

Search Technologies provides implementation and consulting services for both Elasticsearch and Solr.